Share-based payment plans - Valuation assumptions (Details) - $ / shares |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2025 |
Dec. 31, 2024 |
Dec. 31, 2023 |
|
| Disclosure of terms and conditions of share-based payment arrangement [line items] | |||
| Dividend yield (%) | 0.00% | 0.00% | 0.00% |
| Expected volatility (%) | 63.00% | 59.00% | |
| Assumed annual lapse rate of awards (%) | 15.00% | 12.00% | 10.00% |
| Sell price multiple (applied to exercise price) | 2 | 2 | 2 |
| Weighted average share price (in € per share) | $ 0.14 | $ 0.21 | $ 0.86 |
| Minimum | |||
| Disclosure of terms and conditions of share-based payment arrangement [line items] | |||
| Expected volatility (%) | 58.00% | ||
| Risk–free interest rate (%) | 4.35% | ||
| Maximum | |||
| Disclosure of terms and conditions of share-based payment arrangement [line items] | |||
| Expected volatility (%) | 62.00% | ||
| Risk–free interest rate (%) | 4.75% | ||
| Warrants | |||
| Disclosure of terms and conditions of share-based payment arrangement [line items] | |||
| Assumed annual lapse rate of awards (%) | 2.00% | 2.00% | 2.00% |